title: A measurement setup for direct 17O MRI at 7 T.
abstract: An efficient breathing system was designed for direct (17)O MRI to perform oxygen metabolism studies of the human brain. The breathing system consists of a demand oxygen delivery device for (17)O(2) supply and a custom-built re-breathing circuit with pneumatic switching valve. To efficiently deliver the (17)O gas to the alveoli of the lungs, the system applies short gas pulses upon an inspiration trigger via a nasal cannula. During and after (17)O(2) administration, the exhaled gas volumes are stored and filtered in the re-breathing section to make the most efficient use of the rare (17)O gas. In an inhalation experiment, 2.2 ± 0.1 L of 70%-enriched (17)O(2) were administered to a healthy volunteer and direct (17)O MRI was performed for a total imaging time of 38 min with a temporal resolution of 50 s per 3D data set. Mapping of the maximum signal increase was carried out showing regional variations of oxygen concentration of up to 30% over the natural abundance of (17)O water.
authors.affiliation: Department of Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg, Germany.
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Hoffmann
authors.forename: Paul
authors.initials: P
authors.lastname: Begovatz
authors.forename: Armin M
authors.initials: AM
authors.lastname: Nagel
authors.forename: Reiner
authors.initials: R
authors.lastname: Umathum
authors.forename: Kai
authors.initials: K
authors.lastname: Schommer
authors.forename: Peter
authors.initials: P
authors.lastname: Bachert
authors.forename: Michael
authors.initials: M
authors.lastname: Bock
mesh_terms: D000280:Administration, Inhalation; D000465:Algorithms; D001921:Brain / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010103:Oxygen Isotopes / Q000008:administration & dosage*; D012984:Software
chemical_list: D010103:Oxygen Isotopes; D010100:Oxygen